Polyalkenyl esters of polybasic organic acids plastic composition and methods of manufacture



United States Patent POLYALKENYL ESTERS 0F POLYBASIC ORGANIC ACIDSPLASTIC COMPOSITION AND METHODS OF MANUFACTURE Harry H. Beacham, SevernaPark, Md., and Leo S. Burnett, Scarsdale, N.Y., assignors to FMCCorporation, New York, N.Y., a corporation of Delaware No Drawing.Continuation-impart of application Ser. No. 270,175, Apr. 3, 1963. Thisapplication Apr. 20, 1967, Ser. No. 637,320

16 Claims. (Cl. 260-40) ABSTRACT OF THE DISCLOSURE This applicationdiscloses polymer gels derived from poly-unsaturated, unconjugatedthermosetting monomers and particularly those derived from polyalkenylesters of polybasic organic acids, that can be prepared by polymerizingthe monomer to a point of substantially complete acetoneinsolubility (ofthe order of under acetone solubles based on total gel). The gel is infinely divided form and is prepared in the form of a finely dividedfiller impregnated with an addition polymer of a polyethylenicallyunsaturated, unconjugated thermosetting monomer, converted to a gel thatis substantially insoluble in acetone and contains residualunsaturation, the ratio of filler to polymer being at least equal to theratio at which the oil absorption of the filler is just satisfied by themonomer from which the polymer is derived. The finely divided gelcompositions are used in making molding compositions comprising a fillerand a binder comprising (a) a polymer derived from a polyalkenyl esterof polybasic organic carboxylic acid, in the form of a finely dividedgel which is substantially completely insoluble in acetone, ([2) anunsaturated monomer, (c) a linear polyester derived from difunctionalalcohol and dibasic acid, and (d) a catalyst in concentration sufficientto convert the binder to the insoluble state at molding temperature.

The method of making the plastic composition comprises mixing (a) afiller with (b) a liquid polyalkenyl ester of a polybasic organiccarboxylic acid in such proportions that the liquid is present in anamount not above that necessary to satisfy the oil absorption of thefiller, and (c) a polymerization catalyst comprising a peroxide stableat a temperature of at least 120 C., heating the mixture to atemperature to induce polymerization of the ester, continuing theheating through the exotherm developed and until the ester is convertedto a point where less than 10% remains soluble in acetone, and thenconverting the resultant products to a fine powder.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is acontinuation in part of United States Patent Application No, 270,175,filed Apr. 3, 1963.

BACKGROUND OF THE INVENTION Field of the invention polymers are allthermosetting resins. The components of these resins can be reacted instages, to first form solid ice soluble, fusible, storable polymers ofmoderate molecular weight which are, at this intermediate stage of cure,compounded with fillers, pigments, solvents and the like, to producecompositions which can be formed into films, laminated structures andmolded articles and which can then be converted into the insoluble andinfusible state by further treatment, generally by using heat with orwithout catalyst. These polymers are known as condensation polymersbecause they polymerize in large part by elimination of water betweenmolecules.

With the progress of polymer chemistry, it was early recognized that, ingeneral, cross linked thermosetting resins can be made from organiccompounds which contain a plurality of double bonds which areunconjugated with respect to carbon, for example, divinyl-benzene, theallyl acrylates, and especially the polyalkenyl esters of polybasicacids such as the diallyl phthalates. However, unlike the condensationpolymers, the preparation of useful, soluble, fusible intermediates isnot a simple matter.

In the case, for example, of the polyalkenyl esters of polybasic acidssuch as the diallyl and dimethallyl phthalates, polymerization is easilyinduced by peroxide catalysis and heat; but useful products are noteasily obtained. In general, such a polymerization, whether in mass, insuspension or in emulsion form, gels to an insoluble, three-dimensionalnetwork while the major portion of the monomer is still unreacted; andthe gelled mixture, containing a major portion of monomer, is no longerreadily useful in the preparation of films, laminates or moldingcompositions. If polymerization is stopped even just short of gelation,so much monomer remains that further conversion is slow and isaccompanied by excessive shrinkage. As a result, such polymers were notcommercially useful until the discovery of a method of separatingmonomer from the polymer in the ungelled polymerization mixture justprior to gelation, as taught by Pollack, Muskat and Strain in U.S.Patents 2,273,891, 2,370,578 and 2,377,095. As described in thesepatents, monomer is polymerized, at low conversions, to form a soluble,fusible polymer having residual unsaturation. The soluble polymer isprecipitated with methanol or some other solvent which retains themonomer, and is then isolated for compounding, forming, and final cureto an insoluble resin. This, of necessity, produces a high cost resin,since it means the conversion of only a minor proportion of the monomer,and the recovery and recycling of unreacted monomer.

Despite their high cost,these soluble allylic polymers, generally knownas prepolymers, have found a place in industry. They are particularlyvaluable for the production of molded parts which show excellentelectrical properties, particularly under conditions of high humidity.They mold especially well and cure with minimum shrinkage, so that theyare useful in the preparation of parts which require accurate molding;and they are useful in the production of laminates since they canproduce superior laminates under relatively low pressure conditions, sothat they are useful in the treatment of many sorts of bases (forexample, wood veneer) which would be crushed if they were laminatedunder high pressure.

In the twenty years which have elapsed since the method of preparationof prepolymers by separation from unreacted monomer was first developed,a great deal of effort has gone into the problem of reducing their costwhile retaining their excellent properties, by improving the efficiencyof the method. One line of attack has resulted in improvements in themethod of separating prepolymer from monomer-see, for example, Andersonet al., US. Patent 2,613,201, Oct. 7, 1952. However, only relativelysmall cost reductions are obtainable in this fashion.

A second line of attack has been the improvement of percentageconversions before gelation by the use of various control agents.Markedly higher conversions are possible by adding certain solventswhich act as chaintransfer agents (for example, carbon tetrachloride) tothe polymerization reaction mixture, but unfortunately, the resultingsoluble polymers do not possess the desirable properties of the standardmaterials. Some success has been obtained by the use of catalysts whichpermit improved conversions before gelation. These have succeeded inincreasing the original conversions from the order of 20 to 25% up tothe 35% range. However, this has not been sufficient to reduce allylicprepolymers to a cost range where they would be anything but specialtymaterials for uses in which they are unique.

The necessity for drastic action was realized very shortly after theseparation method was developed. Muskat, one of the inventors of theoriginal separation method, early suggested (in US. Patent 2,403,112,issued July 2, 1946) that the gels obtained might be used to producemolding compounds without separation of prepolymers. He polymerized inthe usual fashion, to a gel containing 20-25% polymer, and thencontinued heating to increase the percentage of polymer vis-a-vismonomer, to a preferred range of 50 to 75% of acetone insolubles. Henoted that moldability of his product declined rapidly above the 75%figure, the product becoming substantially non-moldable, particularlywhen the percentage of acetone-insolubles (a measure of conversion) gotto the 80-85% range.

Co-workers of the inventors herein had worked with the techniquesdisclosed in this Muskat patent in attempts to produce a diallylphthalate molding powder substantially cheaper than the molding powderthen in use, which contained prepolymer prepared from an ungelledpolymerization product by methanol extraction. They confirmed Muskatsfindings that optimum conversion was in the 50-75% range and thatmoldability became very poor as conversion rose above 80%. However,moldability was never really good with gel, even at conversions of 50%;and they never could produce moldings which were competitive with thosemade from prepolymers. Even neglecting the fact that the product wassluggish in following a mold, and even at optimum concentrations ofacetone-insolubles, the gel compositions described by Muskat with orwithout added monomer failed to produce physical properties approachingthose obtainable with isolated prepolymer. When fillers wereincorporated with these gels by ordinary mixing tech niques, themoldings gave flexural and compressive strengths of only about /1 ofnormal. When the compounds were subjected to high shear milling such asis used in rubber compounding and which normally is accompanied bydepolymerization, the physical properties were still far below standard.It was the general opinion that the gel approach to lowering the cost ofallylic phthalate resins had failed.

SUMMARY OF THE INVENTION We have now made the discovery that, contraryto the experience of the art, gels derived from poly-unsaturated,unconjugated thermosetting monomers and particularly those derived frompolyalkenyl esters of polybasic organic acids can indeed be used toprepare molding and laminating compositions and can produce compositionscomparable with and often superior to those obtained with standardprepolymers, provided (a) polymerization is carried to the point ofsubstantially complete insolubility (of the order of underacetonesolubles based on total gel), (b) the gel, preferably mixed witha major portion of filler, is in finely divided form, and (c) the gelledpolymer is mixed with additional soluble unsaturated polymerizablematerial. Surprisingly, under these conditions, the finely dividedinsoluble gel particles react with the additional added unsaturatedpolymerizable material, and more surprisingly, yield compositions whichare actually markedly stronger than similar compositions with similartotal quantities of the same polymerizable materials, all added insoluble form.

We do not know just why our materials give such excellent results whilegels containing solubles give poor results. One hypothesis is that whengels containing solubles are mixed with soluble co-reactants, theyswell, and the set core of the resultant swollen mass just cannot begotten to for reaction. Hence, in such gels, much of the converted resinis present merely as inert filler. As the percentage of insolublesreaches above about the amount of this material which cannot be reactedgets so high that molding becomes ditficult to impossible. In our case,on the contrary, the finely divided, substantially insoluble but stillunsaturated gel is available for reaction, there being insufiicientswelling to prevent completion of reaction through the particle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to produce theinsoluble gelled polymer of this invention, we have found it extremelydesirable to mix the soluble polymerizable liquid monomer (or partiallypolymerized monomer) which produces the insoluble gel with finelydivided filler, in such ratio that the liquid never exceeds about theoil absorption of the filler. At about this point and below, themixture, after conversion to the insoluble gel state, breaks up veryreadily into the fine particles essential for our purpose. Moreover, itis possible, by using such high ratios of filler to monomer, to get thedesired degree of conversion directly from monomer in relatively shorttimes.

We have been unable to obtain the desired degree of conversion in bulkpolymerizations, since typical conversions at the point of gelation arewell under 50% and the heat transfer obtainable throughout the gels isvery poor. Emulsion polymerization has likewise proven of no avail sincepressure would be necessary to get the high temperature essential forobtaining the desired degree of conversion, and the diallyl phthalateand other esters are hydrolyzed by water under the necessarytemperature-pressure conditions. The desired complete polymerization canbe obtained by suspension polymerization in inert suspending agents suchas low melting alloys; but such agents are rather messy, and there areditficulties with mainttenance of suspension, and with separation ofpolymer from the suspending agent.

Our method of polymerizing in the presence of finely divided filleravoids all these problems. By operating with no more than aboutsufficient liquid to satisfy the oil absorption of the filler, theresultant solid polymer derived from the liquid is kept essentiallyseparated by the individual filler particles, so that substantialcemented large masses of product are not obtained, and the resultantmass can be readily ground.

Oil absorption can be measured by ASTM Method Dl483-60; it is the pointwhere a mixture of filler and the liquid wetting it changes from amixture of discrete lumps to a paste which does not break or separate,as the liquid is added drop-wise to the mass while stirring with aspatula.

We obtain more easy grinding with rapid conversion, by still anothertechnique. As catalyst for the conversion, we use peroxides ofrelatively good heat stability, of the order of C. and higher, e.g.,dicumyl peroxide, tertbutyl perbenzoate. These peroxides are used inconventional quantity, generally 0.5 to 5% by weight of monomer. Themixture of filler, monomer and catalyst is then heated to an oventemperature of the order of 120 C. or more, depending on the particularcatalyst used. The temperature selected is sufiicient to cause thecatalyst to produce an exothermic polymerization which drives themixture up to a temperature of the order of to 250 C. In general,conversion is sufiiciently complete either at the end of the exotherm orshortly thereafter to reduce the acetone-solubles down to about 10% orless. The cake is then cooled and ground for incorporation withadditional soluble reactants, with or without filler, mold releaseagents, coloring matter or the like to prepare the final moldingcompositions.

The grinding of the gelled cake is very much facilitated by the methodof preparation. Since the shrinkage in going from monomer directly tocompletely insolubilized polymer is of the order of 12% with diallylphthalate, for example, the resultant mass is highly strained, so thatit breaks up easily. Additional strain is derived from the hightemperature attained in the exotherm, whereby the brittleness of themass is enhanced, so that grinding can be carried out at ordinarytemperatures.

In these finely divided gel-filler combinations, some of the gelledresin is dispersed over or coated on the filler particles, but much ofit can be seen under the microscope as independent particles of resin.Even in compositions which contained enough monomer to satisfy the oilabsorption of the filler, the filler is not completely coated; calciumcarbonate filler, for example, can still be decomposed by dilute aqueousacid which has no effect on the polymer. These novel compositions,produced in accordance with our invention are fine powders comprised of50 to 90% of filler and to 50% of substantially insolubilized polymersderived from poly-unsaturated, unconjugated organics; they are useful inthe production of the novel molding compositions described herein.

In the preparation of our finely divided insoluble gel compositions, wehave used a variety of monomers. Diallyland dimethallyl-, ortho, iso andterephthalates, maleates, hexahydrophthalates and chlorendates have allbeen used with good results, as well as the diallyl and dimethallylesters of various aliphatic acids such as succinic, fumaric, etc.Similar polyalkenyl esters of other polybasic acids are likewise usefulin our invention, and it would appear that the invention is useful withother polyunsaturated, unconjugated thermosetting monomer systems. Goodresults can also be obtained from diethylene glycol bis(allyl carbonate)and diallyl and dimethallyl esters of acids such as diglycolic,carbonic, adipic, oxalic, sebacic, azelaic, trimellitic and pyromelliticacids.

In preparing molding compositions from any of our powdered,filler-insolubilized gel polymer compositions, the same monomer may beused as is used in making the filler-gelled polymer mixture, or someother polyalkenyl ester of a polybasic acid may be used. However, as iswell known, the polymerization rate of these monomers is rather slow, sothat it is desirable to use, as part of the soluble portion of themolding, or laminating composition, an unsaturated condensation-typelinear polyester such as is obtained by reacting a glycol with anunsaturated dibasic acid such as maleic acid, in combination with apolyalkenyl-polybasic acid ester. In addition, mono-unsaturated monomerssuch as styrene may be added to cut the cost. The liquid monomers arepreferably used as such, or they may be partially polymerized to a loworder of molecular weight; such partially polymerized soluble liquidsmay be considered monomeric for the purpose of making moldingcompositions from gel powder in accordance with this invention.

Since the gelled insoluble resin still has residual unsaturation, itcombines with the added soluble unsaturated materials to form thebackbone of the finished plastic composition after molding orlamination, and conversion. Because the gel structure will not shrink,it permits moldings to be made which are superior to those made in itsabsence, and in fact superior in some properties to those made withprecipitated soluble prepolymer.

The preferred soluble additives are, as indicated above, mixturescontaining monomers which are polyalkenyl esters of polybasic acids; andunsaturated polyesters. The ratios of ingredients used depend to someextent on the nature of the polyesters. These can be highly reactive,such as the maleates derived from simple glycols such as ethylene,propylene and diethylene glycols, or less reactive, such as mixedmaleate-phthalate esters of high equiv alent weight glycols such as thehydroxy alkyl ethers of bisphenol. When the glycol used is a simpleglycol of low equivalent weight, the acid component of the polyestershould comprise from 40 to weight percent of unsaturated acid, such asmaleic, fumaric, etc.; as the equivalent weight of the glycol goes up,the minimum percentage of unsaturated acid goes up. With high equivalent weight glycols such as the hydroxy alkyl ethers of bisphenol, thepercentage of unsaturated acid, of total acids in the polyester, shouldbe from about 65% to 100%.

When polyesters derived from simple glycols of low equivalent weight areused, reacted with high propormonomers such as styrene and the like, canbe substituted in whole or in part, with only minor disadvantages infinal properties.

Optimum results seem to be obtained with about 40 to 60% of insolublegel polymer, and 60 to 40% of solubles, based on the totalpolymerizables, and with polyester and monomer varying from ratios toeach other of from3to1tolto3.

The amount of filler used depends on its oil absorption and the use towhich the compound is put. With low oil absorption fillers, we have madecompositions for molding in which the filler has ranged from about 60 to80% of the total compositions. With high oil absorption fillers,satisfactory dry mixtures which can be used for molding can be made withfrom about 50 to 75% filler. Where the product is used for laminating,lower proportions of filler are used.

A conventional catalyst for the system is, of course, necessary toinsure curing of the molding or laminating composition. Any free radicalgenerating catalyst which remains active at the molding temperature maybe employed. Since molding temperatures of the order of C. areconventional, the preferred catalysts, from cost considerations, aretert-butyl perbenzoate and dicumyl peroxide. In general, from about 0.1to 1.0% catalyst based on total molding powder is employed, although theeffective amount necessary obviously depends both on the formulation ofthe composition'and on the particular catalyst used; and with anyparticular composition and catalyst, may be more or less than indicated.

Moldings prepared from the new molding compositions of this invention,when compared with compositions prepared from identical raw materials,but with the polymerforming ingredients in the soluble form, exhibitequivalent to superior electrical properties, and far superior physicalproperties. In fact, the electrical and physical properties of our newmolding compositions compare very favorably with moldings in whichsubstantially all the polymer-forming components comprise solubleisolated prepolymer such as diallyl phthalate prepolymer, despite thefact that in the compositions of our invention, the filler loading ismarkedly higher than can be used with prepolymer alone.

As indicated above, it is essential in practicing our invention toconvert our poly-functional monomer to the point where they have verylittle to no acetone-solubles left in them while still retainingresidual unsaturation, i.e., almost complete conversion (about 90% ormore) to gel. To get conversion from monomer to insoluble gel incommercially practical times, the mixture of monomer, catalyst andfiller should be heated to an oven temperature which will induce anexotherm with the particular catalyst used, but which, at the same time,is not so high as to destroy the catalyst before the reaction iscomplete. For example, with diallyl orthophthalate, tertiary butylperbenzoate and a calcium carbonate filler (Duramite), in an ordinaryoven, a temperature of 120 C. minimum is required to produce theexotherm and which then carries the reaction up to about 200 C. If,however, oven temperatures are above 160 C. sufiiciently high conversionis not obtained, due apparently to the fact that a substantial part ofthe catalyst is destroyed before the exotherm is reached. When conveyortype ovens are used, the rate of travel and temperature profile are soregulated that the exotherm is induced and maintained.

With other monomers, the temperatures necessary to produce the desiredreactions vary somewhat. Diallyl isophthalate is somewhat more reactivethan diallyl phthalate, yielding an exotherm at 110 C. under the aboveconditions. Diallyl maleate is even more reactive, the exothermbeginning just below 100 C. and reaching 240 C. within a few minutes.Diallyl hexahydrophthalates and diallyl chlorendates react verysimilarly to diallyl phthalate. The dimethallyl compounds are somewhatmore sluggish than the diallyl compounds, yielding lower exotherm peaksand being more difiicult to completely convert.

We have used a wide variety of water insoluble, inert, inorganic fillersin preparing our products. Calcium carbonate, both precipitated and wetground types, has proven to be a very useful filler because of its lowcost, its low oil absorption, low abrasiveness and good electricalproperties. Calcium carbonate fillers yield compositions with excellentcompressive strength but with less desirable fiexural strengths.

Acicular calcium silicate (Wollastonite) has considerably higher oilabsorption than the calcium carbonate, but its needle like crystal habitgives molded compositions somewhat better fiexural strengths. It isextremely interesting that in the process of this invention, powderedWollastonites generally show higher fiexural strengths than fibrousgrades. Silica has been used, but is generally so hard and refractory tothe grinding mills that it is uneconomical. Hydrated clays tended tocause premature decomposition of the peroxide catalyst and to preventthe desired insolubilization of the gel. However, calcined clays did notshow this effect and were quite useful. Any other finely divided fillercan be used with due attention being given to the desired end use.However, fibrous fillers are not economical for use in theinsolubilization process, since on grinding of the cake, the fibrousmaterial of the filler is destroyed. Where fibers are wanted in thefinal composition, they can be added in untreated form to the powderedcombination of filler and insolubilized polymer or added to the solublepolymerizable materials, in the preparation of the final moldingcomposition.

Other fillers which can be used in practicing this invention caninclude: chalk, limestone, calcium sulfate (anhydrous), barium sulfate,asbestos, glass (powdered), quartz, aluminum trihydrate, aluminum oxide,antimony oxide, inert iron oxides, and ground stone such as granite,basalt, marble, limestone, sandstone, phosphate rock, travertine, onyxand bauxite.

In the preparation of the cake of filler and gel, processability isenhanced by the use of wetting or coupling additives, such as lauricacid, stearic acid, metal soaps such as zinc and calcium stearate,unsaturated silanes and the like. These wetting agents lower theapparent oil absorption of the fillers with the monomers employed, andpermit larger concentrations of filler to be used vis-a-vispolymerizables, at equivalent final physical properties. Moreover, theyhelp to prevent separation of monomer during processing. Apparently, thefillers are wet more readily at high temperatures than at roomtemperatures, so that a filler apparently wet at room temperaturewithout a wetting aid, will spew monomer on heating, and a mass of resinwill separate and end up in a partially converted unsatisfactory form.Hence, We prefer to either use wetting agents, or mill under high shearin their absence, to insure adequate dispersion of filler and monomerbefore polymerization.

The monomer, filler, and catalyst are mixed under conditions whichinsure good wetting; a sigma-blade type mixer or blender is adequatewhere small amounts of a wetting agent are used. This mixture is placedon trays and placed in an oven; if the mixture is at the oil absorptionpoint, this may be an ordinary air-circulation oven, or a tunnel ovenWith a conveyor; if the mixture is below the oil absorption point and isthus porous, an inert atmosphere is used in the oven. The oven is at atemperature of to C., depending on the monomer and catalyst used. Anexotherm is generally induced within about 30 to 90 minutes, and thetemperature of the cake goes up, to the order of to 250 C. The cake isheld in the oven for a total of about 1 to 2 hours, and then discharged,broken up and finely ground. The grinding may be done in hammer, ball,roller or other mills. In general, we prefer to grind to a particle sizeof the order of 100 mesh, although satisfactory results are obtained atabout 40 mesh and finer; there seems to be no lower limit to particlesize which is useful, but obviously grinding be comes uneconomic as itapproaches 200 mesh and finer.

These powders containing insolubilized polymer are then blended, in aribbon or similar blender, with the soluble polymer forming ingredientswhich are in liquid form, and with coloring matters, additional powderedor fibrous fillers, mold release agents, catalyst, etc. The resultantmixture is a fluffy powder, which is densified in conventional fashion,e.g., by passing over a two-roll mill, or by being forced through anextruder-to produce the desired molding compounds. Where non-fibrous orshort fibered fillers are used, the densified product breaks up quiteeasily into free flowing granules, which can be fed into molds inconventional fashion. Where long fibered fillers are used, the densifiedproduct tends to cling together somewhat, so that somewhat different butstill conventional handling techniques are used.

The following examples are given as typical of our invention, withoutbeing limiting thereof..1n the examples, all parts are by weight.

Example 1.Diallyl phthalate composition To 100 pts. of diallyl phthalatemonomer were added 3 pts. tert-butyl perbenzoate and 2 pts. lauric acidand the mixture warmed with stirring until a clear solution wasobtained. The solution was then combined with 450 pts. finely dividedcalcium carbonate (Duramite) and mixed in a Hobart blender until asmooth stiff paste resulted; this represents a filler to liquid ratiojust at oil absorption. This was spread on an aluminum foil-covered trayin a sheet about three-fourths inch thick and placed in a circulatingair oven at 120 C. A thermocouple placed in the center of the cakeindicated that a gradual increase in temperature occurred as the masswarmed to about 120 C. in thirty minutes. The rate then increasedappreciably reaching a peak of C. after a total elapsed time of 55minutes and then slowly dropped back to oven temperature in anadditional 50 minutes.

The hard but brittle cake was removed from the oven, cooled and thenground to a particle size of less than 100 mesh in a Fitz Mill Model MComminuting Machine. Acetone extraction of the finely ground cake for 24hrs. in a Soxhlet extractor showed that 94% of the allylic monomer hadbeen converted to insoluble crosslinkcdresins.

To prepare a molding compound from the gelled polymer 50 pts. of alinear unsaturated polyester resin, prepared from equimolecularproportions of di-(4-hydroxy propoxyphenyl)propane and fumaric acid bythe procedure given in U.S. Patent No. 2,662,069, were dissolved in anequal weight of diallyl phthalate monomer. The solution was catalyzedwith 3 pts. tert-butyl perbenzoate and 2 pts. lauric acid was added as amold lubricant. To this, 550 pts. of the finely ground gelled cake wasadded and the compound sheeted on, a cold two-roll rubber mill. Theresulting compound exhibited excellent compression and transfer moldingcharacteristics. Data obtained on compression molded parts at 2000p.s.i., five minutes at 300 F. are given in Table I.

Example 2.Diallyl isophthalate composition The procedure of Example 1was repeated except that diallyl isophthalate was substituted fordiallyl phthalate in the preparation of the gel. In this case theexotherm began at 105 C. or slightly lower than with diallyl phthalateand reached a maximum of 205 C. Conversion gel and calcium carbonatewere compounded with the diallyl phthalate-polyester composition ofExample 1, a molding compound of excellent properties was obtained.

Example 6.Dimethallyl phthalate composition TABLE I.ALLYLIC MONOMERS INCAKE Example 1 2 3 4 5 6 Shrinkage (in/in.) 0. 004 0. 006 005 008 004009 H.D.T., C 185 239 239 161 200 150 Izod, ft. lbs 0. 33 0. 34 0. 33 0.34 0. 32 0.32

' Rockwell:

M 104 104 106 103 103 102 75 79 82 73 75 71 18, 500 20, 210 21, 720 15,360 17, 630 19, 380 500 8, 050 7, 280 5, 550 6, 690 7, 270 1. 60 1.66 1. 79 1. 69 1. 62 1. 65 Moisture Absorp. (percent) 0. 12 0. 09 0. 160. 08 0. 08 0. 11 Spec. Gravity 1. 99 1. 96 2. 01 2.14 1. 95 1. 95 D.C./10" 5. 55/5. 5 34/5. 15 5. 54/5. 4. 34/5. 24 5. 37/5. 22 5. 24/5. 12D.C 10 /10 (wet)- 5 70/5. 42 5. 36/5. 18 5 60/5. 41 5. 41/5. 24 5. 38/5.23 5. 26/5. 14 D.F. /10 005]. 006 005]. 005 006]. 006 005]. 004 006/.004 004/. 004 D.F. 10 /10 (Wet 1- 004/. 006 (106/. 005 007/. 006 006].005 006/. 005 005/. 005 Vol. Resty. (ohm cm.) 9.1)(10 4. 7X10" 1.1X10 6.8X10" 4. 2X10" 5. 0X10 Surf. Resty. (ohm) 4. 3X10 1. 5X10" 2. 6X10" 2.0X10" 3. 3X10 1.1X10" Vol. Res. (R.I.) 6.0)(10 6. 3X10 8. 8X10 6. 3X106.3)(10 8. 3X10 Vol. Res. wet (hrs.) B 2. 5X10" B 2. 5X10 2. 5X10 b6.3X10 2. 5X10 d 2. 6X10 a 720 hrs. b 48 hrs. a 168 hrs. 6 336 hrs.

to insoluble polymer was 92%. Results obtained on compounding in thediallyl phthalate-polyester composition of Example 1 were substantiallythe same except that a higher heat deflection temperature was achievedin molded articles. Properties are listed in Table I.

Example 3.-Diallyl maleatecomposition Example 4.Diallyl chlorendatecomposition The gel composition of Example 1 was repeated using diallylchlorendate in place of diallyl phthalate in the preparation of thegelled cake. Results substantially identical with Example 1 wereobtained. In addition to the other excellent properties, av high levelof fire retardance was also obtained.

Example 5 .-Diallyl hexahydrophthalate composition Diallylhexahydrophthalate was substituted for diallyl phthalate in the gelportion of Example 1. The peak exotherm obtained was 200 C. and theconversion to insoluble polymer was 99.6%. When this finely ground Thevarious properties reported above are all measured under the testmethods indicated below:

Heat Deflection Temperature, ASTM D-648, two /2" x /2 x 4" bars.

Izod Impact, ASTM D-256, five /2" x /2" x 4" bars cut in two to give atotal of 10 specimens. Measures impact strength.

Compressive Strength, ASTM D-695, five A" x /2" x 4" bars. Hardness,ASTM D-785, any piece.

Flexural Strength and Modulus of Elasticity, AST M D-790, five Mr" X /2"x 4" bars.

Dielectric Constant (DC) and Dissipation Factor (DE), ASTM D-150, two A"x 2 discs.

Volume and Surface Resistivity, ASTM D257, two A3" x 4 discs.

Volume and Surface Resistance (long term), Mil-M- 14F, two /s" x 4"discs.

Moisture Absorption (48 hr.), ASTM D-570-59aT, two /a x 2" discs.

Example 7.Diallyl phthalate-Wollastonite composition damp porous mass.This was placed in an oven heated to C. through which a slow stream ofnitrogen was passed to maintain a partial inert atmosphere. A thermo- 11couple placed in the mass indicated that an exotherm to 200 C. occurredapproximately 50 minutes after plac- Results of Examples 7, 8, 9 and 10are shown in Table II.

TABLE II Example 7 8 9 10 H.D.T. C- 223 262 145 163 Izod (ft. lbs.) 0.35 0. 41 0.31 0.33 Compressive (p.s.i.). 29, 180 36, 430 27, 200 27, 420Rockwell:

M 110 113 105 108 E 90 99 80 88 Flexural (p s i 11, 270 11,350 0, 42010. 620 Modulus X 10 1.81 2. 41 1.28 1. 09 Water Absorp. (percent) 0. 300. 30 0.21 0. l4 Specific Gravity 2.07 2. 1. 81 1.951 D.C. Ill /10..-5.1/4.9 5. 3/5.1 4. 2/4. 3. 0/3.9 D.C. wet 5. 2/4.0 5. 4/5.2 4.3/4.1 4.0/3.9 D.F. 10 /10 .014]. 010 .011]. 008 .009]. 006 .008]. 005 D.F. wet.016]. 010 012/. 009 013/. 007 010/. 006 Vol. Resty. (ohm cm.) 2. 6X10"1 9X10" 3. 2X10 3 6X10" Surf Resty (ohm).. 1 8X10" 5 1X10 5. 3X10" 311x10 Vol. Rest. (ohm 3. 8 10 4. 2X10" 4. 5X10" 4. 5X10 Vol. Rest. (wet)6X10 l 9.1)( 2. 5X10" I 4. 5X10 a 292 hrs. 720 hrs. 716 hrs.

ing in the oven. Total heating time in the oven was 90 minutes. Oncooling a soft easily pulverized mass was obtained. Acetone extractionshowed that conversion to insoluble polymer was greater than 95%. Thiswas ground in a ceramic ball mill to 100% through a 100 mesh screen.

A syrup was prepared by dissolving 50 parts of a linear polyester ofdiethylene glycol and maleic anhydride in an equal weight of diallylphthalate monomer. To this was added 3 parts dicumyl peroxide, 2 partstris(betaethoxyethoxy)vinyl silane and 2 parts calcium stearate. Thiswas compounded on a cold two-roll rubber mill with 550 parts of finelyground Wollastonite-diallyl phthalate gel. A molding compound exhibitingexcellent characteristics was obtained. Data for compression moldedsamples cured two minutes at 330 F. and 2,000 p.s.i. are listed in TableII.

Example 8 Example 7 was repeated except that the amount of calciumsilicate filler was increased to 900 parts per 100 parts diallylphthalate. Results were substantially the same except that the exothermtemperature reached only 185 C. When 550 parts of this finely groundgel-filler composition were combined with the diallyl phthalatepolyestersyrup of Example 7, a molding compound showing extremely highcompressive strength, approximately 37,000 p.s.i. resulted.

Example 9.-Diallyl phthalate-clay composition Nine parts of dicumylperoxide and six parts of tris- (beta-ethoxyethoxy)vinyl silane weredissolved in 300 parts of diallyl phthalate monomer. This solution wasblended with 750 parts calcined clay (Glomax HE) to form a stifi pastewhich was cured for two hours in a circulating air oven at 120 C. Theresulting hard cake was ground in a Fitz Mill to a fine particle sizeand then combined with 200 parts of polyester-diallyl phthalate syrup ofExample 1 to form a compound of excellent molding and electricalcharacteristics. A one-eighth inch molded disc showed a volumeresistance of greater than 2.5)(10 ohms after exposure to 100% relativehumidity at 70 C. for 720 hrs.

Example 10.-Diallyl phthalaze-silica composition Example 1 was repeatedexcept that finely divided silica was used in place of calciumcarbonate. Results were substantially the same.

Example 11.-Glass reinforced composition 808.5 parts by weight of theground diallyl phthalatecalcium carbonate cake of Example 1 were tumbledwith 7.2 parts zinc stearate. A syrup was prepared from equal parts ofdiallyl phthalate, and the polyester resin (diethylene glycol-maleate)of Example 7; to this syrup 2% of tris(beta-ethoxyethoxy)vinyl silaneand 2% dicumyl peroxide were added. The cake and 82 parts by weight ofsyrup were blended on a two-roll mill to a dry powdery mix. Sixty partsof this powdery mix was stirred into 240 parts of additional syrup; thisthin slurry, the residual cake and 284 parts of half-inch glass fibers(Ferro Chem. HSI) were mixed in a Patterson mixer for 1 /2 minutes toyield a dough like premix.

The composition when molded gave very excellent physicals, particularlyheat deflection temperature, impact and fiexurals; its electricalproperties were excellent, except that the excellent moisture resistancewas lost. Results are shown in the following Table III.

TABLE III Example 11 12 H.D.'1. C.) 300 300 Izod (ft. lbs.) 4.11 1.4Rockwell:

Flexural (p.s.i.)

Compressive Specific Gravity Moisture Absorp. (percent) Less glass, inthe product of Example 11, gives somewhat lower physicals, but muchbetter retention of electricals under high moisture conditions. Thus, acomposition made like that of Example 11, but using only 15% glass onthe total composition, gave results which are compared with those ofExample 11 in Table III.

13 Example 13.Use of diallyl malaria in syrup for molding Example 1 wasrepeated, using diallyl maleate as the monomer in preparing a moldingpowder from the gelled cake. It will be noted, by referring to Table IV,that except for a slightly higher heat deflection temperature, resultsvary but slightly from Example 1.

Example 14.Diallyl maleate composition Example 3 was repeated, usingdiallyl maleate instead of diallyl ph-thalate as the monomer in thesyrup used for preparing the final molding composition. Again comparingresults (shown for Example 14 in Table IV, for Example 3 in Table I), itwill be noted that there are no notable difierences in properties.

Example 15.Styrene composition Example 1 was repeated, except that thesyrup used to make the molding powder consisted of equal parts ofstyrene and the polyester resin of Example 1. As will be noted fromTable IV, the heat deflection temperature is down sharply, as is theflexural strength; but the electrical properties are excellent, and areretained under wet conditions except for volume resistivity. Thus, thecompositions, though not as useful as those with polyalkenyl esters ofpolybasic acids as the added monomers, nonetheless show marked utility.

TABLE IV Example 13 14 15 H.D.'I. C.) 213 250 153 Izod (ft. lbs.) 0. 330. 33 Compressive (p.s.i.) 19, 830 22, 810 Rockwell:

Flexural (p.s.i.). 7, 250 7, 840 5, 990 Modulus (X10 1. 64 l. 78 1. 59Moisture Absorp. (percent) 0. 19 O. 36 O. 11 Specific Gravity 1. 981.99 1. 94 D.C. 10 /10 5.3/5.2 5.5/5.3 5.2/5.1 D.C. wet 5.4/5.3 5.6/5.45.2/5.1 D.F. 10 /10 004/005 006/006 003/.004 D.F. wet 005/.000 007/.007004/.005 Vol. Resty. (ohm-em.) 2.7 1.8X10 Surf. Resty. (ohm). 1.4 10Vol. Rest. (ohm)- 2.5)(10 5.6)(10 Vol. Rest. wet (ohm) B 2.5)(10 b1.6)(10 1.2)(10 384 hrs.

b 456 hrs.

0 1,368 hrs.

Obviously, these examples can be multiplied indefinitely by varying .themonomers and fillers used in preparing the insolubilized gel cake, byvarying the monomers and polyesters in the syrups used for making thecompositions to be molded and/ or laminated, and by using variousfillers, catalysts, mold release agents, pigments and the like.

The compositions of the examples are extremely light colored; they canbe prepared in all colors from white to black by adding the appropriatepigment to the mix used in preparing the molding powder. Untreatedfillers can likewise be used with no eifect on the final properties,provided sufiicient insolubilized gelled polymer is present to meet thelimitations set forth in the claims, which define the invention.

What is claimed is:

1. A composition comprising a finely divided, water insoluble, inert,inorganic filler impregnated with an addition polymer ofpoly-ethylenically unsaturated, unconjugated thermosetting monomerselected from the group consisting of allyl and methallyl esters ofpolybasic organic carboxylic acids, polymerized at a temperature notsubstantially less than 100 C. in the presence of at least 0.5% byweight, based on the total Weight of the polymerizable material, of aperoxide polymerization catalyst to form a gel which is at least 90%insoluble in acetone and contains residual unsaturation, the ratio offiller to polymer being at least equal to the ratiov at which the oilabsorption of the filler is just satisfied by the monomer from which thepolymer is derived.

2. A composition comprising a finely divided, water insoluble, inert,inorganic filler impregnated with an additional polymer of a polyalkenylester of a polybasic organic carboxylic acid polymerized at .atemperature not substantially less than 100 C. inthe presence of atleast 0.5 by weight, based on the total weight of the polymerizablematerial, of a peroxide polymerization catalyst to form a gel which isat least 90% insoluble in acetone and contains residual unsaturation,the ratio of filler to polymer being at least equal to the ratio atwhich the oil absorption of the filler is just satisfied by the monomerfrom which the polymer is derived.

3. The composition of claim 2 in which the filler is selected from thegroup consisting of calcium carbonate, calcium silicate, clay, silica,glass, chalk, limestone, calcium sulfate (anhydrous), barium sulfate,asbestos, quartz, aluminum trihydrate, aluminum oxide, antimony oxide,inert iron oxides, granite, basalt, marble, sandstone, sand, phosphaterock, travertine, onyx and bauxite.

4. The composition of claim 2 in which the polybasic organic carboxylicacid is selected from the group consisting of phthalic, isophthalic,maleic, chlorendic, hexahydrophthalic, terephthalic, succinic, fumaric,carbonic, adipic, oxalic, sebacic, azelaic, trimellitic and pyromelliticacids.

5. The composition of claim 2 in which the polymer is derived fromdiallyl phthalate.

6. A molding composition comprising a water insoluble, inert, inorganicfiller and a binder comprising (a) a polymer derived from a polyalkenylester of a polybasic organic carboxylic acid selected from the groupconsisting of allyl and methallyl esters of a polybasic organiccarboxylic acid, in the form of a finely divided gel which is 90%insoluble in acetone and contains residual unsaturation, the fillerbeing impregnated with the polymer, the ratio of filler to polymer beingat least equal to the ratio at which the oil absorption of the filler isjust satisfied by the monomer from which the polymer is derived, (b) anunsaturated monomer, (c) a linear polyester derived from a di-functionalalcohol and a dibasic acid, at least 40% of which dibasic acid isunsaturated, (a) comprising 30 to 75%, (b) comprising 10 to 30%, and (0)comprising 12.5 to 40%, of all of (a) plus (b) plus (c), and at least0.1% based on the total weight of the polymerizable material, of aperoxide polymerization catalyst to convert the binder to the insolublestate at molding temperature.

7. A molding composition comprising a water insoluble, inert, inorganicfiller and a binder comprising (a) a polymer derived from a polyalkenylester of a polybasic organic carboxylic acid selected from the groupconsisting of allyl and methallyl esters of polybasic organic carboxylicacids, in the form of a finely divided gel which is 90% insoluble inacetone and contains residual unsaturation, the filler being impregnatedwith the polymer, the ratio of filler to polymer being at least equal tothe ratio at which the oil absorption of the filler is just satisfied bythe monomer from which the polymer is derived, (b) an unsaturatedmonomer, and (c) a linear polyester derived from a difunctional alcoholof 2-4 carbon atoms and a dibasic acid at least 40% of which isunsaturated, (a) comprising 35-75%, (b) comprising 10- 30%, and (0)comprising 12.5 to 35%, of all of (a) plus (b) plus (c), and a catalystin concentration sullicient to convert the binder to the insoluble stateat molding temperature.

8. A molding composition comprising a water insoluble, inert, inorganicfiller and a binder comprising (a) a polymer derived from a polyalkenylester of a polybasic organic carboxylic acid selected from the groupconsisting of allyl and methallyl esters of a polybasic organiccarboxylic acid, in the form of a finely divided gel which is insolublein acetone and contains residual unsaturation, the filler beingimpregnated with the polymer, the ratio of filler to polymer being atleast equal to the ratio at which the oil absorption of the filler isjust satisfied by the monomer from which the polymer is derived, (b) anunsaturated monomer, and (c) a linear polyester derived from adi(hydroxyalkyl) ether of bisphenol and a dibasic acid at least 65% ofwhich is unsaturated, (a) comprising 30 to 75% (b) comprising 10 to 30%,and comprising 12.5 to 40%. of all of (a) plus (b) plus (0) and at least0.1% by weight based on the total weight of the polymerizable material,of a peroxide polymerization catalyst to convert the binder to theinsoluble state at molding temperature.

9. A molding composition comprising a water insoluble, inert, inorganicfiller and a binder comprising (a) a polymer derived from a polyalkenylester of a polybasic organic carboxylic acid selected from the groupconsisting of allyl and methallyl esters of a polybasic organiccarboxylic acid, in the form of a finely divided gel which is 90%insoluble in acetone and contains residual unsaturation, the fillerbeing impregnated with the polymer, the ratio of filler to polymer beingat least equal to the ratio at which the oil absorption of the filler isjust satisfied by the monomer from which the polymer is derived, (b) anunsaturated monomer, (c) a linear polyester derived from difunctionalalcohol and dibasic acid, at least 40% of which dibasic acid isunsaturated, (a) comprising 40 to 60%, 'and ([2) plus (c) comprising 60to 40%, of all of (a) plus (b) plus (c), the ratio of (b) to (c) varyingfrom 3 to 1 to 1 to 3, and 0.1% by weight, based on the total weight ofthe polymerizable material of a peroxide polymerization catalyst toconvert the binder to the insoluble state at molding temperature.

10. A molding composition comprising a water insoluble, inert, inorganicfiller and a binder comprising (a) a polymer derived from a polyalkenylester of a polybasic organic carboxylic acid selected from the groupconsisting of allyl and methallyl esters of polybasic organic carboxylicacids, in the form of a finely divided gel which is 90% insoluble inacetone and contains residual unsaturation, the filler being impregnatedwith the polymer, the ratio of filler to polymer being at least equal tothe ratio at which the oil absorption of the filler is just satisfied bythe monomer from which the polymer is derived, (b) a monomericpolyalkenyl ester of a polybasic organic acid, (0) a linear polyesterderived from difunctional alcohol and dibasic acid, at least 40% ofwhich dibasic acid is unsaturated, (a) comprising 30 to 75%, (b)comprising to 30%, and (0) comprising 12.5 to 40%, of all of (a) plus(b) plus (c), and 0.1% by weight, based on the total weight of thepolymerizable material, of a peroxide polymerization catalyst to convertthe binder to the insoluble state at molding temperature.

11. The composition of claim 10, in which (b) is a monomer selectedfrom'the class consisting of diallyl and dimethallyl esters of dibasicorganic carboxylic acids.

12. The composition of claim 10, in which (b) is a diallyl phthalate,and A is derived from diallyl phthalate.

13. The method of making a plastic composition comprising mixing (a) 50to of a finely divided water insoluble inert, inorganic filler with (b)10 to 50% of a liquid polyalkenyl ester of a polybasic organiccarboxylic acid selected from the group consisting of allyl andmethallyl esters of polybasic organic carboxylic acid and in suchproportion that the liquid is present in an amount not above thatnecessary to satisfy the oil absorption of the filler, and (c) 0.5% byweight, based on the total weight of the polymerizable material, of apolymerization catalyst comprising a peroxide stable at temperatures ofat least 120 C., heating the mixture to a temperature of notsubstantially less than C. to induce polymerization of the ester,continuing heating through the exotherm developed and until the ester isconverted to a gel which is at least 90% insoluble in acetone and thenconverting the resultant product to a fine powder.

14. The method of claim 13 in which the liquid is insufiicient tosatisfy the oil absorption of the filler, and the heating is conductedin an inert atmosphere.

15. The method of claim 13 in which the filler is selected from thegroup consisting of calcium carbonate, calcium silicate, clay, silica,glass, chalk, limestone, calcium sulfate (anhydrous), barium sulfate,asbestos, quartz, aluminum trihydrate, aluminum oxide, antimony oxide,inert iron oxides, granite, basalt, marble, sandstone, sand, phosphaterock, travertine, onyx and bauxite.

16. The method of claim 13 in which the polybasic organic c'arboxylicacid is selected from the group consisting of phthalic, isophthalic,maleic, chlorendic, hexahydrophthalic, terephthalic, succinic, fumaric,carbonic, adipic, oxalic, sebacic, azeleic, trimellitic and pyromelliticacids.

References Cited UNITED STATES PATENTS 3,331,891 7/1967 Thomas 2608622,403,112 7/1946 Muskat 26096 3,207,816 9/1965 Dugliss 260866 3 ,221,08110/1965 Sarradin 260864 3,078,249 2/1963 Russel 26040 2,757,160 7/ 1956Anderson 260 40 JULIUS F. ROME, Primary Examiner.

